As dry land deposits of crude oil and/or gas become scarcer, the exploration and development of offshore resources has become a major multi-billion dollar industry.
On Apr. 20, 2010, the Deepwater Horizon (an ultra-deepwater offshore drilling platform/rig) was drilling at the Macondo Prospect when an explosion on the rig caused by a blowout from a high pressure gas pocket killed 11 crewmen and ignited a fireball visible from 56 km away. The resulting fire could not be extinguished and, on Apr. 22, 2010, the Deepwater Horizon sank, leaving the wellhead gushing at the sea floor and causing the largest offshore oil spill in United States history. The Macondo Prospect is an oil and gas prospect in the United States Exclusive Economic Zone of the Gulf of Mexico and located approximately off the coast of Louisiana 60 kilometers (kms) off the shores of Louisiana. The oil spill caused catastrophic environmental damage to marine life and habitat of the coastal marshes along the Gulf Coast, which are the breeding grounds and migratory destination of many species of birds and insects. It has been estimated that a total of approximately 5 million barrels of oil was discharged between the start of the leak on Apr. 20 and eventual capping of the leak on Jul. 15. The environmental and ecological effects are significant and of global importance. These types on incidences may become more common as the offshore industry grows.
With the above in mind, it should be noted that most new crude oil and/or gas developments have been directed to obtaining crude oil and/or gas from deposits beneath the sea bed, sometimes at considerable depths in excess of 1 km below sea level, at these depths water pressure is an important factor to consider and overcome. The Deepwater Horizon was drilling in an area that was approximately 1.5 km below sea level.
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object, a common metric unit for pressure is the Pascal (Pa) and has units of Newton per meters square (N/m2). Water pressure increases linearly with depth at a rate of approximately 10 kPa per vertical meter of water. At a depth of 1 km, water pressure reaches approximately 10 Megapascal (MPa), this is approximately 100 times greater the atmospheric pressure at sea level.
It becomes obvious that when incidents such as the Deepwater Horizon explosion and resultant oil spill as described above occurs at these depths, where extremely high water pressures and no light exist, repairs present an almost insurmountable challenge and likely cannot be accomplished. There are, in reality, only two viable options. The first option is to plug the leak, again being very difficult given the extreme water pressure and lack of light. The preferable second option is to contain and direct the oil spewing from the well to the sea surface for capture and recovery.
In the past, attempts have been made to provide a system, an apparatus or a method for containing and/or trapping crude oil/or gas from an offshore well blowout for recovery. However, these attempts have shown to have some deficiencies and are briefly discussed herein below.
U.S. Pat. No. 3,481,294 to Vincent dated Dec. 2, 1969 describes an anchoring system for a drilling vessel, the system including a large diameter vertical pipe, i.e., a riser pipe. The riser pipe is provided with an anchoring system and a chamber contains anchor winches whose cables are connected to anchors in the ocean floor at points surrounding the riser pipe. The anchoring system is made sufficiently strong to moor not only the riser pipe but also a drilling vessel. The drilling vessel is connected to the vertical pipe by a unique system so that the vessel is able to ‘weathervane’ around the pipe. A drawback of the system of Vincent is that it does not propose a system or method for containing an oil spill.
United Kingdom Patent Application No. 2,002,839 to Kovacs dated Feb. 28, 1979 describes a system for confining and controlling a blow-out on oil drilling or production rigs. In order to collect the oil discharged during a blow-out a deflector screen is provided over the derrick, which screen is constructed to direct the oil stream into a collecting basin, which is separated from the main work site. Thereby there will be sufficient time for the working personnel to get away and to activate shut off valves. A shelter 3 in direct communication with the main work site on the rig is provided. A drawback of system of Kovacs is that it does not propose a system or method that is portable or that contains and directs crude oil and/or gas from the leak source to the sea surface.
U.S. Pat. No. 4,318,442 to Lunde, et al. dated Mar. 9, 1982 describes an apparatus for controlling an underwater well blowout including a vessel with a lower weighted collar vent ports intermediate the top and bottom of the vessel a valve controlled chimney at the top of the vessel, a gas outlet positioned to provide a gas cap in the vessel when the valve is closed with the vessel in position around the blowing well, an oil outlet above the vent ports and below the gas cap and means for pumping substantially only oil from the vessel at a rate to prevent oil from escaping from the vessel to the sea in substantial quantities. The method includes the steps of lowering a vessel with a weighted collar, a frustoconical upper section, a valve controlled chimney leading from the upper section, vent parts, an oil outlet above the vent ports and a gas outlet providing a gas cap, over an underwater blowing well with the chimney valve open, seating the vessel on the bottom around and over the blowing well, pumping substantially only oil including entrained gas from the oil outlet and conducting free gas away from the vessel. A drawback of the method and apparatus of Lunde is that it installation of a bulky apparatus at the site of the leak on the sea bed; this may prove to be difficult, especially at extreme depths.
U.S. Pat. No. 4,416,565 to Ostlund dated Nov. 22, 1983 describes a method by collection and separation of oil, gas and water from an offshore oil/gas well and a column for usage by the same. The column comprising a vertically arranged tube with a lower end resting on the sea bed and an upper closed end from which gas may be discharged by gas outlet means. Oil-gas mixture flowing out of a well head in operation of the column will be retarded by an oil column in the tube, thereby releasing gas which is collected in the upper portion of the column. Motion of the oil at the surface of the oil column will be very small, oil thereby flowing over an overflow rim into an overflow channel, from where oil is transferred to the sea surface by oil outlet means. The motion of the mixture may be additionally dampened by horizontal webs. The column may be operated at sea depths more than 300 meters and at shallow water where the column may be constructed as part of a platform. A drawback of the method and column of Ostlund is that it requires installation of a complex apparatus at the site of the leak on the sea bed; this may prove to be difficult, especially at extreme depths.
U.S. Pat. No. 4,456,071 to Milgram dated Jun. 26, 1984 describes a collector apparatus and collection method for use with a blown-out seabottom wellhead. The collector apparatus, including a collector element with an extended, open base and an upper portion enclosing a volume to receive fluid (substantial quantities of gas and lesser quantities of oil) rising, in the water, from the wellhead, and a riser connected to the collector element and extending thereabove to conduct fluid therefrom, is characterized in that the collector element is adapted for fixable attachment to the ocean floor about the seabottom well head prior to any blow-out, and the upper portion of the collector element further includes a relief passage from its interior to the exterior of the collector apparatus, the release passage adapted to vent excess gas from the collector apparatus during initial stages of any blow-out. In preferred embodiments, the relief passage is valved to allow the passage to be closed after the initial stages of any blow-out to limit escape of released oil and reduce the amount of water collected and the collector includes a drilling port adapted to allow drilling operations to proceed therethrough. A drawback of the collector apparatus of Milgram is that it requires installation over the wellhead and affixed to the seabed prior to a blowout.
U.S. Pat. No. 4,323,118 to Bergmann dated Apr. 6, 1982 teaches an apparatus for controlling and preventing an oil blowout comprising a hollow frustoconical dome which is disposable over the end of a well discharge pipe or an offshore rig discharge pipe. At the top of the hollow dome is an axially disposed main valve for the blowoff of oil or gas escaping from the discharge pipe. A plurality of concentrically disposed two-way valves are disposed at the top of the dome about the main valve. With the main valve and the concentrically disposed valves open for the blow off of liquids and fluids, the dome is lowered over the discharge pipe. When the dome is fully lowered, it seats on the bottom surface surrounding the outlet of the discharge pipe. Concrete is poured around the dome to seal the dome to the bottom surface. Connected to the concentrically disposed valves are conduits for conducting gas and oil escaping from the discharge pipe to a storage facility, such as a barge, tank or the like, when the concentrically disposed valves are open for storing oil or gas. Flexible cables are connected to the concentrically disposed valves for opening and closing the same from remote locations. In the event of a fire, the concentrically disposed valves are selectively closed in the fire zones to shut off a supply of fuel to the fire in the fire zones. A drawback of the apparatus of Bergmann is that it requires installation of a complex apparatus at the site of the wellhead on the sea bed; this may prove to be difficult, especially at extreme depths.
U.S. Pat. No. 4,382,716 to Miller dated May 10, 1983 describes a blowout recovery vehicle for recovering the discharge from underwater wells comprises a large inverted entrapment shell positionable over a well and having overly extending tubes connected by hose means to surface separation and storage equipment. Floatation tanks are connected to the surface by air lines which are actuated to adjust the buoyancy of the device to raise or lower it so that it can be lowered over a well to trap the discharge from the well. In use, the assembled device can be towed by a tug into position or can be assembled in the water at the site and lowered over the well without the necessity of the tug coming into the effluent discharge area above the well. Alternatively, an anchor can be placed in the seabed directly upstream of the well at some distance from the well. The device can be tied to the anchor by a tow line of exact length equal to the distance between the well and the anchor and positioned either to the right or left of the well so that the force of the current will cause the device to swing about the anchor so that guidance from a surface vessel can position the device over the well. A drawback of the system of Miller is that it requires installation of a complex system at the site of the wellhead on the sea bed; this may prove to be difficult, especially at extreme depths.
U.S. Pat. No. 4,417,624 to Gockel dated Nov. 29, 1983 describes a method and apparatus for controlling the flow of fluids from an open well bore, fluidly communicating the surface and a subterranean formation, the apparatus comprising (a) a slideable base; (b) a support positioned on the base; (c) a pipe engaging device positioned on the support above the base to urge a pipe into the open well bore; and, (d) a pipe straightener positioned on the support means to engage the pipe and straighten it above the well bore. A method for using the apparatus of the present invention is also disclosed. A drawback of the method and apparatus of Gockel is that it requires installation of a complex apparatus at the site of the wellhead on the sea bed; this may prove to be difficult, especially at extreme depths.
U.S. Pat. No. 4,568,220 to Hickey dated Feb. 4, 1986 describes a system and a method for controlling and/or capping undersea oil or gas well blowouts are disclosed. The system includes a mound and a road bed prepared about and leading to an undersea well head, a base plate having an anchoring track and secured onto the mound and about the well head, a collar member secured to the base plate above the well head by being connected to the anchoring track thereof, a structure also erected on the base plate adjacent the well head, a capping member secured to the structure, a bag floating on the sea surface above the well head and a flexible hose connected between the collar member and the bag. Preferably, at least portions of the mound and the road bed are formed on shore of a plurality of preformed segments, then transported to and assembled in situ on the sea floor about the well head. Preferably, a remotely controlled device is provided designed to do work about the well head and accommodated on the road bed leading to the well head. A drawback of the system and method of Hickey is that it requires installation of a complex system at the site of the wellhead on the sea bed; this may prove to be difficult, especially at extreme depths.
The prior art described above does not envisage or indeed teach a Subsea Crude Oil and/or Gas Recovery and Trapping System and Method that:                1. Is easily deployable;        2. Does not require installing a complex apparatus or system over the wellhead on the sea bed;        3. Directs the leaking crude oil and/or gas to manageable area on the sea surface; and        4. Contains the leak to minimize negative environmental effects.        
The present invention was conceived and developed having regard to the known prior art and with the purpose of providing a Subsea Crude Oil and/or Gas Containment and Recovery System and Method.